The invention relates to the coupling of an axle member to a vehicle leaf spring or a spring-loaded longitudinal link.
German Published Patent Application No. 38 41 846 describes a coupling between an axle and a leaf spring, in which the leaf spring is clamped centrally between elastomer bodies at the point of intersection with the axle. The coupling between the elastomer bodies and the leaf spring is achieved by frictional engagement. Due to the short spring travel in the vertical direction and in the transverse direction, the stiffness of the system is greater in these two directions than in the longitudinal direction.
The compliance in the longitudinal direction is superimposed on the compliance of the suspension to give an amount that results in an unwanted longitudinal shift of the axle, especially in the case of load reversals.
It is an object of the present invention to minimize the vibrations of the body of a vehicle with a rigid axle that are excited by the vehicle drive, irregularities in the roadway and unbalance of the wheels. According to the present invention, the rigid axle is coupled to the body by leaf springs or longitudinal links. To improve ride comfort, the vibration-damping elements may be harder in the transverse and longitudinal directions than in the vertical direction.
The above and other beneficial objects of the present invention are achieved by providing a coupling as described herein. The axle member is coupled to a vehicle leaf spring or a longitudinal link with spring/damper elements therebetween. Arranged between the axle member and the vehicle leaf spring or the longitudinal link are at least two spring/damper elements, which, in the direction of travel, are arranged in front of and behind the section of the axle member to which the leaf spring or the longitudinal link is coupled. The stiffness of the spring/damper elements is greater in the horizontal directions than in the vertical direction.
The structure-borne noise energy that excites the rigid axle to vibrate is produced primarily by the engine and by the drive line and introduced into the rigid axle via the differential. Similarly, the transmission of structure-borne noise produced by other types of excitation, such as irregularities in the roadway and unbalance of the wheels, from the rigid axle to the body is reduced.
The soft coupling in the vertical direction results in damping or deadening of structure-borne noise transmission and thus of the noise within the vehicle. In addition, this arrangement is unproblematic for ride dynamics. The hard connection in the transverse and longitudinal directions of the vehicle is advantageous for the ride dynamics. This coupling may be used for single- and multi-layer leaf springs with and without interlayers, quarter and three-quarter elliptic springs, semi- and full elliptic springs, parallel arrangement of a main spring with an additional spring, etc.